A. Field of the Invention
The present invention relates to compositions, uses thereof, and methods of vaccinating cattle, particularly cows and heifers, against Leptospira borgpetersenii serovar hardjo (type hardjo-bovis) by using Leptospira interrogans serovar hardjo (type hardjoprajitno).
B. Description of the Related Art
Leptospirosis is the most widespread zoonotic disease in the world. It affects most mammals and is an important cause of reproductive failure in cattle throughout the world. (See Faine et al., 1999; Heath and Johnson, 1994.) Leptospires are gram-negative, thin, helical bacteria classified into at least twelve pathogenic and four saprophytic species, with more than 250 pathogenic serovars. The bacteria may survive in the environment for up to six months, preferably in basic soils (pH of 7.2 to 8.0) and in a warm, moist environment. The bacteria rarely survive in dry or extreme cold conditions. (See Faine et al., 1999; Heath and Johnson, 1994.)
Pathogenic species persist as chronic infections of the renal tubules of the maintenance host, sometimes causing very little or no disease. Transmission occurs through direct contact with infected urine or by contact through feed or bedding contaminated with infected urine. In cattle, common clinical signs of the disease include reproductive failure, weak calves, abortion, stillbirths, mummification, and agalactia. Shedding of the bacteria in urine may occur for extended lengths of time. Renal lesions may be the direct result of leptospiremia from infection with Leptospira serovars hardjo, pomona, and grippotyphosa. (See Faine et al., 1999; Heath and Johnson, 1994; Ellis, 1994.)
Cattle are the primary maintenance host reservoir for Leptospira interogans serovar hardjo (type hardjoprajitno) (LHP) and Leptospira borgpetersenii serovar hardjo (type hardjo-bovis) (LHB). LHP is found primarily in Europe, whereas the most common cause of leptospirosis in cattle throughout much of the world is LHB. LHB is the only hardjo serovar that has been isolated to date from cattle in the United States. (Bolin, et. al., 1989(a).)
Vaccination with whole cell inactivated leptospiral vaccine containing Leptospira serovars hardjo, canicola, pomona, grippotyphosa, and icterohaemorrhagiae is the primary means of controlling leptospirosis in cattle. Because the costs associated with the manufacture of a vaccine are directly related to the type(s) and number of components used to formulate the vaccine, it is desirable to reduce the number of components in the vaccine without loss of vaccine effectiveness. Herein, are described vaccines, as well as associated methods and uses that provide protection against Leptospira borgpetersenii serovar hardjo (type hardjo-bovis) without including the serovar hardjo (type hardjo-bovis) in the vaccines.